1. Field of the Invention
The present invention relates to a die casting machine.
2. Description of the Related Art
A die casting machine is provided with a pair of dies, a fixed die plate and a movable die plate for holding these dies, a clamping unit for opening, closing, and clamping the dies, an injection apparatus provided with a plunger and sleeve for injecting and filling molten metal into a cavity formed between the dies, etc.
In this due casting machine, to facilitate removal of the casting from the dies, the practice has been to coat a release agent on the inner surface of the cavity of the dies before casting. Further, to reduce the friction between the sleeve and plunger of the injection apparatus when injecting the molten metal into the cavity of the dies, the practice has been to coat a lubricant on the inner circumference of the sleeve before casting.
As the release agent and lubricant, in the past frequent use has been made of water-based release agents or water-based lubricants comprised of a release material or lubricating material dissolved in water. Recently, in place of these, powder release agents and powder lubricants comprised of powder materials have begun to be used.
Powder release agents and powder lubricants have various advantages compared with water-based release agents and water-based lubricants such as an easing of the temperature shock on the dies, reduction of entry or gas into the casting, high heat insulating effect due to the formation of an evaporating film, improvement of the release performance, reduction of noise, and lack of need for waste water treatment.
To get the powder release agent and powder lubricant to exhibit sufficient performance, however, it is necessary to cause them to uniformly disperse and deposit on the surface of the cavity of the dies and the inner circumference of the sleeve.
To coat a powder release agent on the surface of the cavity of dies, for example, the method is adopted of spraying the powder release agent into the cavity in a state with the dies clamped.
With this coating method, however, depending on the shape of the cavity etc., it is difficult to cause the powder release agent to uniformly disperse to the surface of the cavity. Unless the powder release agent is uniformly coated, the performance of the powder release agent cannot be sufficiently exhibited.